Cement finish grinding:\nCement clinker is typically reduced to fine powder predominantly by which mill?

Introduction / Context:
Cement manufacture ends with finish grinding, where clinker and gypsum are ground to a fine powder. Traditional plants use long, compartmentalised ball mills—commonly called tube mills—for this duty, sometimes in combination with high-efficiency separators. Recognising this classic equipment choice is common in plant operations exams.

Given Data / Assumptions:

• We refer to conventional (non-HPGR) circuits.
• Final product fineness is cement powder (Blaine in hundreds of m^2/kg).

Concept / Approach:
A tube mill is essentially an elongated ball mill with multiple compartments for coarse and fine grinding stages, optimised for clinker grinding. Crushers (roll/hammer) perform coarse size reduction of raw materials or clinker prior to milling; they cannot achieve cement fineness. Modern plants may use roller presses with ball mills, but the classical answer remains the tube mill for finish grinding.

Step-by-Step Solution:

Verification / Alternative check:
Process flow diagrams of legacy cement plants show tube mills with separators as the standard finishing step.

Why Other Options Are Wrong:

• Roll/hammer crushers: pre-grinding/coarse crushing only.
• Ball mill (short): can be used, but the industry-specific term for clinker finish grinding is tube mill (long ball mill with compartments).
• Pin mill: used for soft chemicals, not clinker.

Common Pitfalls:
Equating any “ball mill” with the cement-specific “tube mill;” the latter is the recognised configuration for finish grinding.

Final Answer:
Tube mill (long ball mill)